Well UFC is tough to get into, and there is an long vetting process, hence when you say UFC, youtalking a fulltime job on par with other professional athletes. When u say "for fun"....that is another issue. Guys that do it for fun may train to peak right before an event, and then not train much at all. I'd say an amateur doing it for fun probably puts in 10 to 15 hours per week including running, lifting, mat work etc, all while going to work.